IV 
CONTENTS 
Most Criticai, Episode in Evolution, by W. K. Brooks ... 121 
Serial Affinities of Siluric Formations in Northeastern 
Missouri, by Charles Keyes and R. R. Rowley . . . 131 
Geological Age Characteristics of the Coals, by John J. 
Stevenson.139 
Geological Work of R. Ellsworth Call, by Charles Keyes . 151 
Editorial : 
Passing of a Venerable Mining Industry, 161; Origin of Oldest 
Fossils, 162; Geological Science and the State, 164 
Structural Geology : 
Vanishing of Eastern Coal Seams in Indiana, by W. N. Logan, 
167; Giant Bay Bar of Ancient Bonneville Lake, by C. Keyes, 
167; Thrust at Crow’s Nest, by C. Keyes, 169; Biplanation of 
Earth’s Straticulate Crust, by C. Keyes, 170; Flextures in 
Canadian Front Ranges of Rockies, by C. Keyes, 171; Some 
Prairie Tectonics, by C. Keyes, 175; Tectonic Setting of Utah’s 
High Plateaus, by C. Keyes, 176 
April Number 
Major Features of Earth’s Surface, by Carl Diener ... 17? 
Nephrite Celt from Bahia, Brazil, by Henry S. Washington . 198 
Tectonic Setting of Laccolithic Genesis, by Charles Keyes . 203 
Natural Bridging in the High Plateaus, by Frederick J. Pack . 213 
Ore-Deposition in Trunk-Channels, by Charles Keyes . . 226 
Editorial : 
Last Message from Branner, 231; Passing of Murchison’s 
Siluria, 233; Unveiling of Calvin Portrait, 235 
Stratigraphical Geology : 
Scope of Cretacic Sedimentation in Andean Geosyncline, by E. 
W. Berry, 241; Yorkic Period in Stratgraphy, by C. Keyes, 
243; Derivation of Peter Sandstone, by C. L. Dake, 244; Com¬ 
plexity of Peter Sandstone, by C. Keyes, 245; Extension of 
Triassic Coal-field in North Carolina, by J. H. Pratt, 246; 
Muscogee Shales of Western Interior Coal-field, by C. Keyes, 
248; Wide Extent of Texas Potash Formations, by J. A. Ud- 
den, 249; Mid Ordovicic Volcanic Ash in Tennessee, by W. 
A. Nelson, 251; Galena Limestone as a Terranal Title, by C. 
Keyes, 252; Late Cretacic Formations in English Cannel, by 
M. Charcot, 255; Dakotan Sandstone in Missouri, by C. Keyes, 
256 
May Number 
John Casper Branner, by Charles Keyes.257 
Earth’s Future Miror’d on Face of Mars, by G. H. Hamilton . 267 
Hippurites from South America, by Edvfard W. Berry . . 272 
Climatic Influences in Vadose Ore Deposition, by C. Keyes . 275 
Taxonomic Significance of Peter Sandstone, by C. L. Dake . 288 
Secular Changes of Geological Climates, by Marsden Manson . 301 
Eral Affiliations of Grassy Black Shale, by Charles Keyes . 307 
